The present invention relates to insulated containers for the storage and transport of frozen, fresh, chilled or processed foods and other perishable or temperature sensitive products or materials. In particular, the invention relates to an insulated container having a cover for slidably moving within the inner cavity of the container.
During the transport and storage of frozen, fresh, chilled or processed foods, such as seafood, bakery, candy, ice and other perishable or temperature sensitive products or materials, it is essential that the goods be kept at a prescribed storing temperature. To transport large volumes of temperature sensitive goods, refrigerator vans with individual freezing systems have been used. However, transport of small amounts of goods to one or a few retailers or consumers with a refrigerator van is expensive and slow. Because of high freight costs, many frozen goods are transported on conventional vehicles which leads to quality losses and damaged goods.
To maintain temperature sensitive goods at the prescribed storing temperature without the use of an external power source, insulated containers or chests have been utilized for the transport and storage of the temperature sensitive goods. To allow easy filling of the insulated containers and to prevent heat or cold loss, insulated containers have included an insulated cover or top which fits above or is supported by the side walls of the container.
Insulated containers with side wall suspended tops have several drawbacks. Because the top is supported by the top edges of the side walls, the position of the top on the container is permanently fixed. If the temperature sensitive goods do not fill the insulated container, a dead air space is created between the temperature sensitive goods and the top of the insulated container. This dead air space acquires an equilibrium temperature with the adjacent temperature sensitive goods. As this happens, previously chilled goods warm up and previously heated goods cool down. Moreover, this additional air space must also be insulated. As a result, the insulating efficiency of the insulating container is reduced.
In addition, because the top of the container is supported by the side walls, the side walls must be strong enough to support the weight of the top as well as any other containers which are place on top of the container. To meet this strength requirement, the side walls must either be constructed of a stronger, more expensive material or be made thicker to accommodate the additional weight. As a result, these high strength side walls either increase the cost of the container or, in the alternative, reduce the storage capacity of the container.